Providing spinning transmission through mated and engaged gears to make mechanical tools operating as desired is a commonly adopted technique.
For instance, U.S. Pat. No. 7,537,064 discloses a portable power tool that includes a housing, a motor with an output means, a driven element and a transmission means. The transmission means is located in the housing to receive spinning input from the output means of the motor, then a spinning output is generated and transmitted to an output shaft. The transmission means includes a plurality of planetary transmission stages each has an annular gear, a planetary bracket and a plurality of planetary gears. The planetary gears are held by the planetary bracket to engage with the annular gear.
R.O.C. utility patent M390361 discloses a power generation apparatus that converts kinetic energy generated by compression of wheels to electric power. It includes movable press plates on roads or rails run over by the wheels, holders beneath the movable press plates and a plurality of magnetic elements of the same polarity between the movable press plates and holders that are repulsive with each other. The movable press plates are located higher than the roads or rails, and include a gear rack on a lateral side and first, second and third gears at one side of the gear rack to transmit kinetic energy. The first gear is engaged with the gear rack and second gear, the second gear and third gear have respectively a transmission shaft in the center. The second gear and transmission shaft are interposed by a one-way bearing so that the second gear can spin only in one direction. The second and third gears are interposed by a volute spring. The third gear is engaged with a gear of a power generator. The movable press plates run over by the wheels generate kinetic energy released through the volute spring to drive the third gear spinning to drive the gear of the power generator to generate electric power.
All the aforesaid techniques provide transmission via a plurality of gears that generally are divided into a driving gear to receive power input, a transmission gear engaged with and driven by the driving gear, and a driven gear engaged with and driven by the transmission gear. The gears are engaged for spinning, and wearing takes place after a prolonged period of time that results in gradual reducing of tooth thickness and increasing of gear intervals. As a result, vibrations and noises are generated and operation sensitivity decreases during the machine tool is in operation, or even cause damage of the machine tool. Hence the gears with thinner teeth have to be replaced frequently. This causes a lot of troubles and higher repairs and maintenance costs for the machine tool in use. There are still rooms for improvement.